During initial construction of an elevator or in any later elevator modification a situation may arise where repositioning of elevator components that have been installed earlier is beneficial or even necessary. A need to reposition arises for instance in construction-time elevators, particularly in connection with a process for extending the service zone to reach higher in the elevator hoistway. In this type of elevator arrangements, which are also known as jump-lifts, the bottom part of an elevator hoistway is put to use already before the building has been completed. The top part of the elevator hoistway can be under construction at the same time as an elevator car moving in the bottom part of the elevator hoistway already serves people on the lower floors of the building. Generally in jump-lifts the elevator car moving in the lower parts of the elevator hoistway is supported by a movable supporting structure positioned above the car in the hoistway. The installation work in parts of the elevator hoistway above this support structure is performed from a working platform movable in the elevator hoistway above the support structure. The installation work may comprise, among other things, the installation of guide rails and electrification in the elevator hoistway. When the elevator hoistway under construction above the supporting structure has reached a sufficient stage of completion, the completed part of the elevator hoistway can be put to use. At this stage a jump-lift is performed, where the supporting structure is lifted and mounted in a higher position in the elevator hoistway. These steps may be repeated until the desired height has been reached. Elevators often comprise a roping system having one roping suspending the elevator car and the counterweight, and another roping which is suspended by the elevator car and counterweight. This type of setting of the roping system is desirable for numerous reasons, for example because it provides rope weight compensation and it may be used for tie-down function. In jump-lift type elevators having this type of roping system, however, the lifting stage poses challenges. The lifting of the support structure may cause a need to adjust the relative position of the movable elevator units and the roping system. Particularly, in order to maintain the lowest landings within the service zone of the elevator car, a longer roping is needed for suspending the elevator car and the counterweight. Typically, each of said two separate ropings has had a rope supply at an end thereof so as to enable the feeding of more roping to the roping system. The existing solutions have the drawback that they necessitate several ropings the route of which cannot be freely chosen. Also, several rope supplies are needed, the location of which cannot be freely chosen. In particular, the existing solutions are not flexible with regard to the suspension ratios during the construction time. This often means that the elevator must undergo radical changes when converting the construction time elevator into a final elevator, because often the construction time suspension ratio cannot be chosen to be the same as that of the final elevator. The drawbacks related to the suspension ratio are usually caused by the need to position the rope supply separately from the moving elevator units, for example to save energy and space. For this reason the suspension ratio for the elevator car and/or counterweight needs to be 2:1, which leaves the rope ends free to pass to the rope supply which is positioned for example in the pit or on the landing or on the support structure. A later conversion of the elevator into 1:1 suspension ratio then necessitates changing routes of the ropes. It may also necessitate major changes to the shaft layout and structure of the car frame and/or counterweight frame.